package dhtpdud;

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Java_4_5 {
	public static void main ( String[] args )
			throws java.io.IOException {
			
			int jumsu;
			char hakjum;
			String iput;
			
			System.out.println("***** result *****");
			System.out.print("Input jumsu : ");
			InputStreamReader kkk = new InputStreamReader(System.in);
			BufferedReader bbb = new BufferedReader(kkk);
			iput = bbb.readLine();
			jumsu = Integer.parseInt(iput);
		
			switch( jumsu / 10 )
			{
			case 10:
				hakjum = 'A';
				break;
			case 9:
				hakjum = 'A';
				break;
				
			case 8:
				hakjum = 'B';
				break;
				
			case 7:
				hakjum = 'C';
				break;
				
			case 6: 
				hakjum = 'D';
				break;
				
			default:
				hakjum = 'F';
				break;
			}
			
			System.out.println("Hakjum : "+hakjum);
	}
}
